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Biomedical subjects

J Prosser

Publications and source records attributed to J Prosser.

52 records · Page 3Linked to original sources
PubMed1988

Hydrogen-mediated enhancement of hydrogenase expression in Azotobacter vinelandii.

Azotobacter vinelandii cultures express more H2 uptake hydrogenase activity when fixing N2 than when provided with fixed N. Hydrogen, a product of the nitrogenase reaction, is at least partly responsible for this increase. The addition of H2 to NH4+-grown wild-type cultures caused increased whole-cell H2 uptake activity, methylene blue-dependent H2 uptake activity of membranes, and accumulation of hydrogenase protein (large subunit as detected immunologically) in membranes. Both rifampin and chloramphenicol inhibited the H2-mediated enhancement of hydrogenase synthesis. Nif- A. vinelandii mutants with deletions or insertions in the nif genes responded to added H2 by increasing the amount of both whole-cell and membrane-bound hydrogenase activities. Nif- mutant strain CA11 contained fourfold more hydrogenase protein when incubated in N-free medium with H2 than when incubated in the same medium containing Ar. N2-fixing wild-type cultures that produce H2 did not increase hydrogenase protein levels in response to added H2.

Azotobacter↗
PubMed1986

Sequence relationships of three human satellite DNAs.

The simple sequence components of three human classical satellite DNAs have been defined, and some segments of each satellite have been sequenced. Each of the classical satellites I, II and III was found to contain, as a major component, a single family of simple repeated sequences. The three simple-sequence families have been called satellites 1, 2 and 3, to indicate the enrichment of each in one of the classical satellites I, II and III, and to differentiate them from these classical satellites, which also contain other repeated components. Satellite 3, the simple sequence component of classical satellite III, when digested with the restriction endonuclease HinfI, forms a ladder based on a repeat of five base-pairs, 5' A-T-T-C-C. The HinfI ladder was shown to be composed of repeated elements with the general sequence 5' (A-T-T-C-C)n-A-TC-T-C-G-G-G-T-T-G. Satellite 2, the simple sequence component of classical satellite II, is digested by HinfI into a large number of very small fragments, of length 10 to 80 base-pairs. These were found to contain the simple repeat 5' A-T-T-C-C, in a highly diverged form. Analysis of satellite 2 sequences suggested that the five base-pair repeat was originally amplified as a higher-order repeat like that of satellite 3. However, the main tandemly repeated segments of satellite 2 in the human genome are much longer, and the simple sequence elements on which they are based are quite degenerate. Satellite 1, the simple sequence component of classical satellite I, is digested by the restriction endonuclease RsaI into a ladder of fragments less than 150 base-pairs in length. These ladder fragments were found to be formed by the loss of RsaI sites from two related A + T-rich sequences, A (17 base-pairs) and B (25 base-pairs), arranged in alternating arrays, -A-B-A-B-A-. Analysis of a large number of cloned fragments from the RsaI ladder of satellite 1 showed that the tandem arrays, -A-B-A-B-A, have a more complex arrangement, with apparent amplification of segments containing particular sequence variants of the repeat units, A and B. No sequence relationship was evident between the repeat elements of satellite 1 and those of satellites 2 and 3.

Base Sequence↗
PubMed1984

Human satellite I sequences include a male specific 2.47 kb tandemly repeated unit containing one Alu family member per repeat.

A portion of human satellite I DNA is digested by HinfI into three fragments of 775, 875 and 820bp in length which form a tandemly repeated unit 2.47kb in length, specific to male DNA. One Alu family member per repeat is found within the relatively G+C rich 775bp fragment. The 875 and 820bp fragments are highly A+T rich and consist of long stretches of poly dAdT and related sequences.

Base Composition↗
PubMed1982

Simple repeated sequences in human satellite DNA.

In an extensive analysis, using a range of restriction endonucleases, HinfI and TaqI were found to differentiate satellites I, II and III & IV. Satellite I is resistant to digestion by TaqI, but is cleaved by HinfI to yield three major fragments of approximate size 770, 850 and 950bp, associated in a single length of DNA. The 770bp fragment contains recognition sites for a number of other enzymes, whereas the 850 and 950bp fragments are "silent" by restriction enzyme analysis. Satellite II is digested by HinfI into a large number of very small (10-80bp) fragments, many of which also contain TaqI sites. A proportion of the HinfI sites in satellite II have the sequence 5'GA(GC)TC. The HinfI digestion products of satellites III and IV form a complete ladder, stretching from 15bp or less to more than 250bp, with adjacent multimers separated by an increment of 5bp. The ladder fragments do not contain TaqI sites and all HinfI sites have the sequence 5'GA(AT)TC. Three fragments from the HinfI ladder of satellite III have been sequenced, and all consist of a tandemly repeated 5bp sequence, 5'TTCCA, with a non-repeated, G+C rich sequence, 9bp in length, at the 3' end.

Base Composition↗
PubMed1981

Buoyant density and hybridization analysis of human DNA sequences, including three satellite DNAs.

Total human DNA was fractionated from the three types of Cs2SO4 gradient used to prepare satellites I, II and III. Three satellite DNAs were found: satellite I with a mean buoyant density of 1.6888 g/ml comprising about 1.3% of the total, satellite II with a mean buoyant of 1.696 g/ml, comprising about 1% of the total an satellite III with a mean buoyant density of 1.699 g/ml comprising about 2.2% of the total. The buoyant densities of these satellites after purification were 1.686, 1.694 and 1.697 m/gl, respectively. A preparation with the attributes of satellite IV was isolated from the shoulder region of a satellite III preparative gradient. In situ hybridization using complementary RNA showed that the three satellites were located predominantly on chromosomes 9, Y, 15 and 1. Satellite II also showed marked hybridization to chromosome 16. Satellites I and II and III cross-hybridized to each other but satellites I and II did not. On the basis of our hybridization data, we suggest that some of the same sequences which comprise satellite III also comprise satellite I an II.

Animals↗
PubMedDate not supplied

Mouse small eye results from mutations in a paired-like homeobox-containing gene.

Small eye (Sey) in mouse is a semidominant mutation which in the homozygous condition results in the complete lack of eyes and nasal primordia. On the basis of comparative mapping studies and on phenotypic similarities, Sey has been suggested to be homologous to congenital aniridia (lack of iris) in human. A candidate gene for the aniridia (AN) locus at 11p13 has been isolated by positional cloning and its sequence and that of the mouse homologue has been established (C.T., manuscript in preparation). This gene belongs to the paired-like class of developmental genes first described in Drosophila which contain two highly conserved motifs, the paired box and the homeobox. In vertebrates, genes which encode the single paired domain as well as those which express both motifs have been described as the Pax multigene family. A Pax gene recently described as Pax-6 is identical to the mouse homologue of the candidate aniridia gene. Here we report the analysis of three independent Sey alleles and show that indeed this gene is mutated and that the mutations would predictably interrupt gene function.

Alleles↗
PubMedDate not supplied

Treatment of an unusual case of masochism.

Masochistic sexual activity is potentially dangerous, rarely reported voluntarily, and hard to treat. This article describes a masochist patient who received sexual gratification from being burnt or crushed. Antiandrogen medication, serotonin uptake inhibitor, and psychodynamic psychotherapy along with sexual education and social-skills training and aversive behavior therapy were all tried over a period of 9 months. The response was measured by effects of treatments on the frequency of erotic fantasies and masturbation. Antiandrogens and aversive behavior therapies may be the most effective treatments for such cases, at least in the short term, although the underlying social deficits and the need to reshape the sexual behavior ought to be addressed in the long term.

Adult↗
PubMedDate not supplied

The Functional Pain Scale: reliability, validity, and responsiveness in an elderly population.

OBJECTIVES: Because of difficulty experienced in assessing pain in frail older patients and the lack of pain assessment tools with standardization in the elderly, the Functional Pain Scale (FPS), an instrument incorporating both subjective and objective components to assess pain, was developed and evaluated. DESIGN, SETTING, PARTICIPANTS, AND MEASURES: One hundred subjects more than 65 years old participated in the validity, reliability, and responsiveness (the clinical sensitivity of the instrument to change) testing of the Functional Pain Scale. Subjects were recruited from a geriatrics inpatient setting, a geriatrics outpatient setting, and a local hospice (residing in their homes). Ninety-four of the subjects completed all phases of testing. Reliability was tested using a test-retest format and a correlation matrix. Criterion-related validity was established as compared with the Visual Analog Scale (VAS), the Present Pain Intensity (PPI), the McGill Short Form Questionnaire (MPQ-SF), and the Numeric Pain Scale (NPS) instruments. Responsiveness for the FPS, the VAS, the PPI, the MPQ-SF, and the NPS instruments was determined using five previously described techniques: effect size, standardized response means, relative efficiency, direct comparison of t test scores, and direct comparison of P values. A cumulative index was developed to rank each scale. Cumulative responsiveness index scores were based on individual scale performance for each separate responsiveness test. The lowest score in the cumulative responsiveness index indicated the most responsive scale. RESULTS: Interrater reliability for instruments tested exceeded 0.95 for all instruments tested. Validity testing showed high correlations as well (r = 0.62, r = 0.85, r = 0.80, r = 0.90 for the VAS, the PPI, the MPQ-SF, and the NPS respectively). Responsiveness evaluated overall by the responsiveness index was best for the Functional Pain Scale (7) followed by the Visual Analog Scale (12), the Present Pain Intensity (13), the McGill Pain Questionnaire-Short Form (19), and the Numerical Pain Questionnaire (24). CONCLUSIONS: The Functional Pain Scale was determined to be reliable, valid, and responsive. The responsiveness of the Functional Pain Scale was superior to the other instruments tested. The Functional Pain Scale is an acceptable instrument for assessing pain in older adults and may reflect changes in pain better than other instruments tested. Further testing in other populations is warranted.

Journal Article↗
PubMedDate not supplied

Social needs of people with mild learning disabilities.

Community care requires us to pay closer attention to the social and health needs of people with learning disabilities. However, much of the care is focused on people with moderate to profound learning disabilities. Perhaps the needs of those with milder disabilities could be neglected and so individuals could lose out on the support they need. This care study describes the care delivered to a woman who has mild learning disabilities. The aim is to raise people's awareness of the needs of people with mild learning disabilities so they may be met in the future.

Adult↗